I’m so truly sorry for your loss 
My father passed away after a very long illness & was embalmed before my sisters & I went to see him over 2 weeks later.
I have mixed feelings on it really, I wanted to say goodbye & felt like I needed to see him for it to be real (you might find you won’t feel this way as you were with him when he passed I don’t know) but a lot of me regretted it, he didn’t look like himself, his skin was very red & almost purple he had gotten very big with the illness so this probably effected things (sorry if this is too much info but I would have a appreciated a heads up in hind sight) my grandfather who I also saw after he died didn’t look like this he was thin & white after suffering from cancer but did look at peace although we didn’t have to wait as long to see him that we did for my dad.
However it did help confirm he was gone as I saw him the night he died waving goodbye. For me I guess I needed it as the illness was a very long one & we had years of him being on the brink & then pulling through so I couldn’t almost believe it when it finally happened.
My sisters & I wanted to put a personal letter in the coffin each which we did but honestly part of me wishes I’d of given it to the undertaker to put in.
My advice is to go with your gut on the day you honestly won’t know really know, the undertakers will understand and as others have said ask the undertakers advice, they are very professional.
It has taken me a long time to remember my dad in a happy light but it would have probably taken me a while anyway regardless if I had saw him after or not.
I hope it goes ok for you. As you say it’s personal & don’t beat yourself up if you regret whatever decision you end up making you can only do what you feel is best for at the time. Thinking of you &
your family.